If we let know our callers that we have not done anything, they will be able to optimize their decisions.
Cc: stable@kernel.org Fixes: b4012002f3a3 ("[media] uvcvideo: Add support for control events") Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Ricardo Ribalda ribalda@chromium.org Message-ID: 20250224-uvc-data-backup-v2-1-de993ed9823b@chromium.org Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Hans Verkuil hverkuil@xs4all.nl (cherry picked from commit ba4fafb02ad6a4eb2e00f861893b5db42ba54369) --- drivers/media/usb/uvc/uvc_ctrl.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index 69f9f451ab40..47e3e5e5c670 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1734,12 +1734,17 @@ int uvc_ctrl_begin(struct uvc_video_chain *chain) return mutex_lock_interruptible(&chain->ctrl_mutex) ? -ERESTARTSYS : 0; }
+/* + * Returns the number of uvc controls that have been correctly set, or a + * negative number if there has been an error. + */ static int uvc_ctrl_commit_entity(struct uvc_device *dev, struct uvc_fh *handle, struct uvc_entity *entity, int rollback, struct uvc_control **err_ctrl) { + unsigned int processed_ctrls = 0; struct uvc_control *ctrl; unsigned int i; int ret; @@ -1774,6 +1779,9 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, else ret = 0;
+ if (!ret) + processed_ctrls++; + if (rollback || ret < 0) memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP), @@ -1792,7 +1800,7 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, uvc_ctrl_set_handle(handle, ctrl, handle); }
- return 0; + return processed_ctrls; }
static int uvc_ctrl_find_ctrl_idx(struct uvc_entity *entity, @@ -1839,6 +1847,7 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
if (!rollback) uvc_ctrl_send_events(handle, ctrls->controls, ctrls->count); + ret = 0; done: mutex_unlock(&chain->ctrl_mutex); return ret;